Recycling water?

Shaun · Post by **Shaun** » 06 Dec 2006, 03:30

Most cities are on heavy water restrictions here, due to a drought. Does anyone have any thoughts on recycling/renewing/cleaning my water removed during water changes so it can be returned to the tank?
I'm thinking of plant filters and filtration through carbon or other material...any ideas? Is it bad, good, indifferent? Obviously its not a closed system, zero waste sort of idea, but anything to cut back on water useage is good.

Shaun

snowball · Post by **snowball** » 06 Dec 2006, 08:29

This is something I've been thinking a lot about recently, it would be great to be able to recycle as much tank water as possible. I think the main limitation, at least for me, is lack of space as I imagine you would need the system to hold at least 10 - 20 times the quantity of water you go through every time you change water on the tanks.

I was thinking of either a large pond or a trough and using a lot of plants like reeds and water hyacinth that are most efficient at taking up nitrogen. The water would need to be recirculated for a period of time, preferably through some sort of baffle arrangement to maximise contact with the plants, and ideally with a solar powered pump that has a battery for night operation.

When the nitrate and phosphate levels are reduced sufficiently, the water could be pumped to a small storage tank to ready it for the water change(s). Here it could be heated and filtered through carbon and UV steralization, which should make it good enough to drink.

I think the best place to look for ideas would be in the sewage treatment business and the self-sufficient eco housing trade, techniques used in those fields will be proven technology and should be able to be adapted to a smaller scale.

MatsP · Post by **MatsP** » 06 Dec 2006, 10:34

Alternatively, you could use the waste-water for other purposes - some obvious ones:
1. Watering plants/lawn/etc (the extra nitrate is a bonus).
2. Flushing the toilet - you don't REALLY need really clean water for this purpose, right?.

--
Mats

snowball · Post by **snowball** » 06 Dec 2006, 10:42

Oh of course it would be fine for such uses, although here the trend in cities is turning towards rainwater tanks that are plumbed directly to 'grey water' appliances such as loos and garden taps. Ideally it would all be integrated into a system where as much water is retained on-site and reused rather than flushed or washed away.

However I would still like to find a feasible way to purify water change water to a level fit to put back into a tank, as there is a limit to how many hundreds of litres I can put on our postage stamp sized garden!

MatsP · Post by **MatsP** » 06 Dec 2006, 11:56

How about the underground aspect?

--
Mats

Shaun · Post by **Shaun** » 06 Dec 2006, 22:54

Thanks for the responses guys

I already have a few things setup to use rainwater, grey water, excess water (ok, we shower with buckets

).
This water is used for flushing toilets and watering the garden, but as Snowball pointed out: theres only so much water you can use on a small garden...I think my vegie patch is arousing suspicion amongst the neighbours! We're on Stage 4 water restrictions, so gardens cannot be watered with anything but waste water...which is what I'm doing, but I do have a lot more waste water then other households due to the tanks.
Also I'd like to be prepared to hang onto my fish if water shortages get any worse.
Shaun

MatsP · Post by **MatsP** » 07 Dec 2006, 10:20

How about donating your fishy water to your neighbours?

--
Mats

rahendricks · Post by **rahendricks** » 07 Dec 2006, 14:35

I seem to recall reading about a pond system that was heavily planted with ginger. Ginger is suppose to be very good at cleaning up water. I believe ordinary pond weed, elodea, is very efficient at cleansing water as well.

Crazie.Eddie · Post by **Crazie.Eddie** » 27 Dec 2006, 16:59

Here's an idea I provided on another forum, to reuse your tank water...

1. Run your waste water from the tank, through a regular canister or wet/dry filter. The return line will go through a UV sterilizer to kill any bacteria/parasites. This water will then be pumped to storage container A.
2. Pump the water from storage container A through an RO/DI filter to filter out excess ammonia, nitrates, nitrites. The filtered water will go to storage container B, but route the waste water line from the RO/DI filter back into storage container A.
3. In storage container B, you will use dosing equipment to add back water nutrients.
4. You may need to add additional water if the level is low, using either RO/DI water or tap water.
5. Pump the finalized water back from storage container B back into the tank.

Keep your tank enclosed, to reduce evaporation. You can then collect the water condensation, which is distilled water. You can run some kind of system to drip the evaporated water into the storage container B used in Step 3.

This should help you reduce the amount of water used.

Bas Pels · Post by **Bas Pels** » 27 Dec 2006, 17:50

Although this last option does have an answer to evaporatiojn problems, I'm afraid the problem is, RO oes remouve all salts, not just nitrates, ammonia and phosphates.

Therefore, you will end up keeping your fish in extreme soft water - which kills them, and very hard water in container A - thus decreasing the RO efficiency.

I think the first solution - weed cleaning, under glass, or another transparant evaporation protection, would be the best - still, you would need much, much more water in storage than in the tank, as stated before. I wonder how many people have that much space?

Crazie.Eddie · Post by **Crazie.Eddie** » 27 Dec 2006, 19:48

Salts and minerals removed from RO/DI systems can be added back in. I believe these are contained in aquarium additives.

It does make the water soft, but you can use additives to increase the hardness and aragonite to increase the pH.

Bas Pels · Post by **Bas Pels** » 27 Dec 2006, 21:39

Crazie.Eddie wrote:Salts and minerals removed from RO/DI systems can be added back in. I believe these are contained in aquarium additives.

It does make the water soft, but you can use additives to increase the hardness and aragonite to increase the pH.

Apparently these salts are elsewhere much less expensive than in Europe. I've worked with these salts, en demiwater, and still, it was a lot of money and a lot of work (but required for the research)

bronzefry · Post by **bronzefry** » 29 Dec 2006, 14:20

Eddie,
Is a wet/dry filter powerful enough to get the water through an RO filter? I'm not criticizing. I'm just curious. I think it's a nifty idea.

Amanda

rahendricks · Post by **rahendricks** » 29 Dec 2006, 16:12

I don't have any personal experience with RO systems but what I've been told is that they at best only output 50 percent of the water that's input. That doesn't seem like an efficient recycling method. I think a biological process would be the most efficient, but I agree that most people would not have the space required to implement it. Several years ago, the Great Lakes were invaded by the Zebra Mussels, a Eurasian native. Although this is considered to be an ecological disaster, they have actually done a excellent job of cleaning up the water. Has anyone ever experimented with freshwater clams in an aquarium to see their effect on water quality? Finding a way to create a balanced ecosystem within the tank and reduce the amount of water that would need to be changed might be the best answer.

butterfly · Post by **butterfly** » 29 Dec 2006, 16:15

Just had to share this from another site

http://www.plantgeek.net/forum/viewtopi ... highlight=
Coffee anyone? ;)
Carol

Crazie.Eddie · Post by **Crazie.Eddie** » 29 Dec 2006, 19:33

bronzefry wrote:Eddie,
Is a wet/dry filter powerful enough to get the water through an RO filter? I'm not criticizing. I'm just curious. I think it's a nifty idea.
Amanda

If you direct the pump from the wet/dry filter through the RO/DI, then it should. Booster pumps can be used, such as these...
http://www.marinedepot.com/aquarium_rev ... sp?CartId=

bronzefry · Post by **bronzefry** » 03 Jan 2007, 20:20

rahendricks wrote:I don't have any personal experience with RO systems but what I've been told is that they at best only output 50 percent of the water that's input. That doesn't seem like an efficient recycling method. I think a biological process would be the most efficient, but I agree that most people would not have the space required to implement it.

RO does have waste water, which can be a drawback or an advantage. I personally use is for watering the houseplants. They've never looked so good! The Christmas Cacti are flowering like mad.

It may also be used it in tanks that require a higher TDS. The RO output percentage varies, depending on what the water pressure is coming into your house or apartment and how clean the filter is. If you are lucky enough to have good water pressure, you will get the ratio that's listed on the box. If you have less than optimal water pressure, RO filtration can be a waste of time. You will have much more waste than RO. Prior to taking the "RO" leap, it's worthwhile checking into your water parameters directly from the tap. If you have poor water pressure, a water pump may be required, as Eddie suggests. Coralife sells some units with the pump built-in. It's also good to remember that the RO filters have been tested in optimal laboratory circumstances, not a home with fluctuating water quality. I'm fortunate to have high water pressure. That's about all the good I can say about it.
Amanda

Reginator · Post by **Reginator** » 03 Jan 2007, 20:36

Hydroponics can clean the water rather well as long as it's a soil-less system. Although such systems are normally used for growing a certain "herb" if you live somewhere where such things are controlled by laws there are other plants that can be raised using them, although the aforementioned "herb" is probably one of the better plants from the point of view of pollutant removal. Really, any fast growing plant with a high nutrient requirement would be good, and as most such plants produce either something enjoyable or edible you get an added bonus at cropping time! There is also the bonus that with such systems you can use almost any space in the house, eg. attics or basements

snowball · Post by **snowball** » 04 Jan 2007, 00:18

I had also though of using an outdoor hydroponic setup to purify water, although rather than growing "Jamaican tomatoes" in it I was thinking of fast growing food crops like lettuce that could be put on the table or traded with neighbours etc.

I know that many large aquaculture farms use their waste water for hydroponic crops and there is no reason why it can't be done with a smaller system. Obviously there will be quite a bit of water lost to transpiration from the plants, but this is paid off by the return in crops.

kcmt01 · Post by **kcmt01** » 04 Jan 2007, 02:44

I'm just sort of fantasizing here, but wouldn't it be great to build a large greenhouse, raise, oh, say, Pepper cories or Tiger barbs and hydroponic tomatoes and maybe carnations with the waste water being cleaned by the plants and, well, you get the idea...

apistomaster · Post by **apistomaster** » 04 Jan 2007, 02:57

I have been reading about the severe drought and tight water restrictions Australians are facing. Tough position for fish keepers with very many aquariums. Soon this will be a problem for more of us. Finding ways to reprocess home waste water on site is something that many of us are going to be dealing with in the future.
All the biological methods are very demanding of space and even if you can use plants that yield usuable crops there will be high evaporative and transpirational losses and not all wastewater can be used because of toxic chemicals that end up in it from household cleaners and the like.
The current RO technology is terribly inefficient even under optimimum water pressure and temperatures.
In my theoretical designs for an energy and water efficient future fishroom I have been thinking of trying to explore the possibilities of using solar distillation technology. Mounting everything on the roof. Using solar or wind driven pumps to get the waste water to the rooftop solar still, storing the water where it can be warmed by solar and then using gravity to return it to the aquariums. Distillation would allow the use of very poor quality wastewater and would of necessity be designed to mimimize evaporative water loss. While not a miniaturized system it could be far more compact than open marsh plant types of water purification designs.
There is a lot of work to be done to perfect a primarily solar powered system but it seems like some standardized designs could be developed that would work for many fishrooms. Finding methods for a few aquariums would be harder as I think there is some point where the cost benefits would be lost on the very small scale but something needs to be found for the fish rooms of the future.Wherever there is enough rainfall water can be collected to supplement any recycling system. The prospect of growing "Jamaican Tomatoes" can set an aquarist back 5 to 10 years in the current climate of the USA.

bronzefry · Post by **bronzefry** » 06 Jan 2007, 14:54

I think all of us will need to be creative in the not-too-distant future.

I was just filling my new/old 55 gallon tank this past week. Instead of using all "new" water, I used some of the water that I would have normally discarded from my fry tanks. I tested it with a few different modes: electronic TDS and electronic pH monitor. I also used the good old full test kit with the nitrite, nitrate, and on and on. The water was absolutely fine. It wasn't before long that I had the 55 gallon tank filled and partially planted. I didn't realize how much water I was tossing!

Amanda

Bas Pels · Post by **Bas Pels** » 07 Jan 2007, 09:22

In fact, by using old water, you dit yourself another favour: the old water ,coming from healthy tanks, does contain already the good nitrificating bacteria you will be getting by ripening the tank.

In fact, this week I received 4 new tanks, and I filled them all with 75 % old water (they will ripen for 3 weeks, and than I will come back from Uruguay with a lot of wild cought fishes)

Any overdue nitrate will vbe consumed in these 3 weeks by a few plants I'll introduce

snowball · Post by **snowball** » 09 Jan 2007, 01:30

apistomaster wrote:... I have been thinking of trying to explore the possibilities of using solar distillation technology.

That's an idea I hadn't considered until now, so I have had a bit of a look into it and it seems the main limitation is production capacity, although some designs suggest that multiple arrays can be linked together.

There are two levels on which this method works. On a basic level it simply distills water through evaporation. More advanced designs heat the water to above 85 deg Celsius for ten minutes, which effectively pasteurises the water, rendering it safe for human consumption.

Below is a link to a commercially designed system. TDS levels are claimed to be reduced to 1-2ppm, however I am guessing that nitrate levels will not be changed from the levels at which they start at. As such, this would only be of use as a final treatment to water that has been pretreated to remove nitrate. http://www.solarwaterpurifier.com/html/howworks.htm

Other than solar distillation, none of the water treatment concepts that I have as yet looked into will produce water fit for drinking - at best they will treat grey water to a level where it is suitable for irrigation.

It seems that a variety of methods will be required to get fish waste water to a standard where it can be put back in the tank, the question is to find what combination is most effective and efficient for our individual purposes.
I am still leaning towards ideas used in aquaculture / aquaponics, as I feel that it will be necessary to do something more productive with our water than just keep fish in it. Non-essential use of water is fast becoming a luxury in this part of the world, not to mention elsewhere.

rahendricks · Post by **rahendricks** » 09 Jan 2007, 14:39

A good solar distiller should produce water fit for drinking. It would take a lot of collectors to produce enough water for anyone with more than a few tanks. There are electric distillers available that would produce the amount of water necessary. Some are even for converting sea water to drinking water so they should be fine for aquarium waste water. Depending on what your electric rates are they may be expensive to operate, but facing water rationing they may be a viable alternative. This will be distilled water so you would have to add mineral salts to it to make it suitable for aquarium use.

MatsP · Post by **MatsP** » 11 Jan 2007, 12:39

rahendricks wrote:A good solar distiller should produce water fit for drinking. It would take a lot of collectors to produce enough water for anyone with more than a few tanks. There are electric distillers available that would produce the amount of water necessary. Some are even for converting sea water to drinking water so they should be fine for aquarium waste water. Depending on what your electric rates are they may be expensive to operate, but facing water rationing they may be a viable alternative. This will be distilled water so you would have to add mineral salts to it to make it suitable for aquarium use.

Hmm. I don't agree with the marketing people who say that "distilled" or "RO" water is fit for human consumption. Human body needs minerals in the drinking water...

I do agree that the solar powered distillation sounds like a neat thing.

--
Mats

bronzefry · Post by **bronzefry** » 13 Jan 2007, 20:43

Here's an idea:
http://www.drsfostersmith.com/Product/P ... 035+113159
I imagine you'd have to change the water at some point, but it may stretch out the time in between. No water down the drain, either. Maybe a bit of money down the drain, though....

Amanda

snowball · Post by **snowball** » 23 Feb 2007, 11:20

I decided to make an effort to do something about reducing the amount of tap water I use for my tank. I set up an old 4' tank in the garden and filled it with clean tank water (not from the gravel vac) from a large water change on my 300l tank, I estimate about 150l went into the recycling tank. The water out of the 300l tank had a nitrate level of about 20mg/l and phosphate at close to 2mg/l, the plan was to reduce these readings to 0 by means of fast growing floating water plants.

After filling it I added a fair bit of salvinia that I had floating in a temporary pond, then about a week later I got hold of a couple of small water hyacinths. I have been removing about a fist-sized wad of salvinia every couple of days, it seems giving it some room stimulates growth. The hyacinths started sending out pups after a couple of weeks, I intend to let them be the main plant with the salvinia filling in the gaps. There is a small airstone in the tank to provide slow circulation.

The first few photos show the tank after about four weeks. I also added a couple of rows of cuttings of Ludwiga and Hygophyllia suspended in fluro light diffuser, the more roots to take up the nutrients the better.

The vials on the left show the Nitrate (red/orange) and Phosphate (blue) test readings from the 300l tank when it is due for a water change. The vials on the right show the levels in the recycling tank after about four weeks.

After about five weeks both the nitrate and phosphate levels were 0mg/l (according to my test kits at least) and after a couple more days I decided it was ready to use back in my tanks. I drained as much clean water out of the recycling tank as I could, leaving about two inches in the bottom of the tank to avoid the mulm that had accumulated on the bottom. I estimate that I got about 130l of recycled water from this setup, enough to do a weekly water change on the 300l tank.

The water taken from the recycling tank was then put in a 220l reservoir that is used to age tap water, the balance added from the tap to fill the barrel. This water is filtered through a small canister filter (Eheim 2213) and goes through tightly packed filter wool to remove suspended matter and Bio Chem Zorb, an activated carbon combined with ion exchange resins, to remove discolouration caused by tannins and other dissolved organic matter, plus any toxins and heavy metals that may have entered the system via rain. The cannister then sends the water through a UV sterilizer and back into the reservoir - after the time outside the water was teaming with life, I strained out what I could and added it to a nursery tank.

Filtered to remove discolouration etc. I have left it like this for the past week and plan to use it for a water change this Sunday. I'll let yopu know if the fish survive! ;)

Conclusion? A total of six weeks seems a long time to wait for the water to be treated to a quality where it can be re-used for water changes, but I expect the turnover time will be shortened once the water hyacinth takes over and hope to eventually get it down to four including time in the reservoir. That would be a saving of 25%, which is no insignificant amount. As such, I consider this experiment to be successful and is encouragement in the right direction - no doubt a large enough system could be self-sufficient, depending on how much water one needs to go though.

I'll working on was to increase efficiency and will update this thread when there's been improvement to report.

cheers,
Andrew

Bas Pels · Post by **Bas Pels** » 23 Feb 2007, 16:09

This does look like a good idea, but I wonder about a few things:

1 why don't you take weekly say 80 liters from the cleaning tank, add 20 liters tapwater, and replace it with 100 liters tnakwater? This way, your cleaning tank might provide useble water weekly

2 Being European, I have no clue about the quality of rain you have, but if I would adopt your system, I certainly would not: filtrate, decolourate and sterilise the water. I get the idea you managed to kill the best water one can have, resulting in less usable water. I do understand you used the living food though

Still, I whsh we would have enough sun in winter to adopt the idea

Bas

snowball · Post by **snowball** » 24 Feb 2007, 08:55

Thanks for your comments Bas. As mentioned this was the first run so the system is far from refined, but you raise valid points.

1 why don't you take weekly say 80 liters from the cleaning tank, add 20 liters tapwater, and replace it with 100 liters tnakwater? This way, your cleaning tank might provide useble water weekly

I thought of diluting it, but decided to leave it until the Nitrate and Phosphate levels were as low as I could measure. Although it took some time, I'm sure it will be quicker in the future. I also hope to reduce the fish load in that particular tank, which will lessen the frequency of water changes.

2 Being European, I have no clue about the quality of rain you have, but if I would adopt your system, I certainly would not: filtrate, decolourate and sterilise the water. I get the idea you managed to kill the best water one can have, resulting in less usable water. I do understand you used the living food though

I live close to the city and the rain water ranges from a pH of about 4.5 - 5 up to a high of 6 after a few days of rain. There is also a lot of brake dust and diesel soot falling out of the air as I live on a steep and busy road.
The discolouration from tannins is due to the vast amount of wood that is in the main tank, as well as some dissolved organic matter. I'd rather get rid of it from the 'fresh' water as it builds up quickly enough.
I take your point about killing the best water, as the recycling tank is full of daphnia & infusoria etc. Currently I have only a few baby danios to care for so there's not much to do with it, however I do intend to get a few Pacific Blue Eyes Pseudomugil signifer, a fish native to my area, and breed them in the recycling tank where the fry will have abundant food.

As you mention winter, I am curious to see how this will fare over our winter coming up. We don't have to worry about any snow, but my garden loses all but a glimpse of sun between May and August, so I expect that plus the cooler weather will slow things down.

Andrew

Recycling water?

Recycling water?

...

daydreaming...